Spacebug

The other aspect you need to look at is frequency.  The power ratings for most amps are given at 1,000Hz if I remember correctly.  Based on my informal, real-world experience, the IPR2-7500 has more power down low, below 20Hz, which would lead me to the opposite conclusion than yours, which is the IPR2-7500 has the stronger power supply.  But it would be interesting to see if Luke's tests would bear this out so we could have some true data.

I think an amplifiers power output down low (compared to higher frequencies) has more to do with said amps high-pass/DC block filters than how "strong"  the power supply is. 

Hopefully,  some protection circuit would jump in before the ps is in trouble, no matter played frequency. 

Basically the amp with the lowest cutoff freq of the high-pass filter would output more power down low than another,  equally powerful amp would with higher cutoff freq HP filter... 

Just my thoughts though,  nothing tested... 

Ricci, is your listening room closed with a door or open to the rest of the house? 

I ask because in my previous room I had that bump at 6-8hz and a fairly sharp roll off below 5hz when the door was open. 

Closed door resulted in no 6-8hz bump and less drop below 5hz... 

An understandable assumption though.

I guess there isn't too many amps employing switching output stage but does not have a switch mode power supply...

But for example the LG FP series uses SMPS but usual, linear output stages, hence not susceptible to bus pumping, if i'm correct that is...

EDIT: nevermind, brainfart on my behalf, misinterpreted your last post

Interesting read about these amps, waay more power than I need but still interesting

But, from what i've heard bus pumping is not a problem assosiated with SMPS itself but of class-d amplifiers, the amplifier stage itself that is.

If class-d modules don't operate in full bridge mode bus pumping will occur.

The powersupply is not the cause but rather the component that takes the beating of fluctuating rail voltages.

Not sure whether SMPS is more susceptible than "linear" power supplies or not but the main problem comes from class-d amps not operating in full bridge...

In full bridge mode the rail fluctuation caused by one amp "channel" will be consumed by the other, inverted amp channel causing an equal but inverted fluctuation.

In non bridge mode the rail fluctuation is not canceled out by the other channel so the fluctuation reach the powersupply and it is here the problem starts.

That is atleast what i've heard...

 I see on the graph the peak at 10hz is about -8db, does that mean there's another 8db in the tank?

Yes, if a signal is maxed out (0dBFS), a way to make it louder is to place said signal in multiple channels.

The signal is summed together, either by soundwaves in the air if you only use fullrange speakers or in the crossover of say an AVR.

In the crossover the low frequency content of all fullrange channels is summed together with the LFE and then outputted to Sub-out.

Therefore, you can have low frecuency signals higher than the max 115dB wich the LFE can have at 0dBFS, when played back at reference level.

In a 7.1 track you can potentially have little over 10dB louder effects if the same signal is encoded, fully maxed, in all channels.

Can you give a time stamp?

He already did earlier to my request for timecodes, Watched it and yeah, that scene was

The 20-23min mark is all good.  0:21:34-0:22:30 is the graphed scene.

As for Lone Survivor, if people have sealed subs and don't get serious excursion and pressurization from their subs in the noted scene, they either have severe roll-off in their signal chain or not enough subs.  It's legit.

Can you give some approximate timecodes for the scene?

I won't have time to view the movie anytime soon but I think I can manage a little demo viewing